FREQUENCY LIMITS ON NAKED-EYE OPTICAL TRANSIENTS LASTING FROM MINUTES TO YEARS
- Image Informatics and Computational Biology Unit, Laboratory of Genetics, NIA, NIH, 333 Cassell Dr., Suite 3000, Baltimore, MD 21224 (United States)
How often do bright optical transients occur on the sky but go unreported? To constrain the bright end of the astronomical transient function, a systematic search for transients that become bright enough to be noticed by the unaided eye was conducted using the all-sky monitors of the Night Sky Live network. Two fisheye CONtinuous CAMeras operating over three years created a database that was searched for transients that appeared in time-contiguous CCD frames. Although a single candidate transient was found, the lack of more transients is used here to deduce upper limits to the general frequency of bright transients. To be detected, a transient must have increased by over three visual magnitudes to become brighter than visual magnitude 5.5 on the timescale of minutes to years. It is concluded that, on the average, fewer than 0.0040 (t {sub dur}/60 s) transients with duration t {sub dur} between minutes and hours, occur anywhere on the sky at any one time. For transients on the order of months to years, fewer than 160 (t {sub dur}/1 year) occur, while for transients on the order of years to millennia, fewer than 50 (t {sub dur}/1 year){sup 2} occur.
- OSTI ID:
- 21301620
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 138, Issue 3; Other Information: DOI: 10.1088/0004-6256/138/3/956; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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